Download or read book Indoor Air Quality Modeling and Demand Controlled Ventilation written by Steven John Emmerich and published by . This book was released on 1993 with total page 296 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book A MODELING AND MEASUREMENT FRAMEWORK FOR UNDERSTANDING TRANSPORT FATE AND CONTROL OF INDOOR AIR POLLUTANTS written by Gen Pei and published by . This book was released on 2022 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Air pollution is one of the most critical environmental risks to public health. Most of the human exposure to air pollution occurs in indoor environments, where people spend majority of their time (>20 h daily on average). Household air pollution is responsible for four million premature deaths (including 400,000 deaths of children) worldwide each year. Furthermore, indoor air pollution has considerable economic impact due to its association with healthcare expense, worker absenteeism, and poor productivity. To improve indoor air quality, it is necessary to develop energy-efficient engineering technologies (ventilation, filtration, pollutant sensing, etc.), given that buildings consume one-third of energy globally and heating, ventilating and air-conditioning (HVAC) systems account for half of overall building energy use. To develop efficient and effective control measures, it is critical to understand the transport mechanisms of indoor air pollutants based on spatial and temporal scales of pollutant diffusion, deposition, and chemical reactions in indoor environments. Given this background, the overarching objective of my Ph.D. dissertation is to develop and apply a new modeling and measurement framework for studying transport, fate, and control of representative indoor air pollutants (CO2, ozone, exhaled viral aerosols, and particulate matter) at three indoor spatial scales (room scale, near-occupant microenvironment, and indoor surface boundary layer), while considering indoor environmental parameters such as ventilation condition, indoor airflow pattern, occupant activities, and pollutant-surface interactions. Specifically, this dissertation focuses on five primary investigations as follows. The first investigation examines how the non-uniform distribution of CO2 in a room affects the performance of CO2-based demand controlled ventilation (DCV). The results show that CO2 sensor location should be selected carefully depending on indoor airflow pattern and CO2 distribution to optimize the air quality and energy performances of a DCV system. In a room with displacement ventilation and associated CO2 vertical stratification, CO2 sensors placed in return air duct or close to occupants may not accurately reflect air quality within occupant breathing zone, leading to overventilation (with excessive energy use) or inadequate ventilation to the breathing zone. In such a case, wall-mounted sensors at occupant breathing height (e.g., 1.0-1.2 m for seated people) can provide more accurate measurements than sensors at room exhaust. Unlike CO2, some indoor reactive gases such as ozone and radicals can react with indoor surfaces (human skin, clothing, building materials) and alter human exposure to air pollutants by reducing reactant concentration while generating harmful byproducts. The second investigation provides quality control criteria for numerical modeling of ozone reaction with human surfaces in indoor spaces. This study assesses the performances of various turbulence models and near-human grid sizes in computing airflow and mass transfer around a human body. The results suggest that the Large Eddy Simulation (LES) has better accuracy than the Reynolds Averaged Navier--Stokes (RANS) turbulence models in simulating buoyancy-driven thermal plumes and ozone mass transfer near a body. The computational grids adjacent to human surface should have dimensionless wall distance y+ 10 for reasonable simulations of air and mass transfer in near-human microenvironments. To further characterize the transport of reactive gas within boundary layers of indoor surfaces, the third investigation establishes a research framework combining microscope-scanning of indoor surface material and detailed Computational Fluid Dynamics simulation of wall-bounded flow, and applies this approach to predict ozone reaction with a carpet surface. The results reveal that indoor surface properties (e.g., surface topography) can impact turbulent air mixing within the surface boundary layer, thereby modulating ozone mass transfer rate across the boundary layer to the surface. The effective indoor surface area available for ozone uptake notably varies with surface type, near-surface air speed, and turbulent structures within the boundary layer. Besides the research on indoor gaseous pollutants, the fourth investigation examines the transport of airborne aerosols exhaled by infected people in indoor spaces, and evaluates the efficacies of different ventilation strategies in reducing airborne transmission risk of infectious diseases (e.g., COVID-19) in buildings. The study results show that indoor buoyancy-driven airflows (can be found in displacement ventilated rooms or residential rooms without mechanical air mixing) can result in a longer transport distance of exhaled viral aerosols and a higher airborne infection risk than those under mixing airflows. Under displacement ventilation, a 2 m (6 ft) social distance alone may not ensure the prevention of airborne disease transmission in buildings. Consequently, control strategies such as ventilation and social distancing should be considered together for a layered control. Because of the increasing demand for indoor aerosol monitoring, the fifth investigation assesses the potential of using low-cost particle sensors for a long-term monitoring of indoor particles and HVAC system performance. This study deployed low-cost sensors in an office building in Philadelphia for a six-month field test. The results suggest that low-cost sensor can provide useful information for identifying key indoor particle sources and evaluating mechanical system performance such as filtration efficiency. The measurement data indicate that particle resuspension induced by occupants is a major source of coarse particles ( 5 [mu]m) in office environments, while outdoor-indoor penetration is a main source of smaller particles (0.5-1 [mu]m). Overall, this Ph.D. dissertation provides new dataset and methodology to understand transport and removal mechanisms of air pollutants at different time- and space-scales in indoor environments. The study results could help HVAC engineers, building scientists, public health researchers, and policymakers make better-informed decisions for developing healthy, smart, and energy-efficient buildings.

Download or read book Simulations of Indoor Air Quality and Ventilation Impacts of Demand Controlled Ventilation in Commercial and Institutional Buildings written by and published by . This book was released on 2013-12-04 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Carbon-dioxide (CO2) based demand controlled ventilation (DCV) offers the potential for more energy efficient building ventilation compared with constant ventilation rates based on design occupancy levels. A number of questions related to CO2-based DCV exist regarding potential energy efficiency benefits, optimal control strategies for different building types, and sensor performance and deployment. In addition, questions have been raised concerning the indoor air quality impacts, primarily with respect to contaminants with source strengths that are not dependent on the number of occupants. In order to obtain some insight into the issueof IAQ impacts of CO2-based DCV, a simulation study was performed in six commercial and institutional building spaces using the multizone airflow and IAQ model CONTAMW. These simulations compared six different ventilation strategies, with four of them using CO2 DCV, the simulations, performed for six U.S. cities, wereused to compare ventilation rates, indoor CO2 levels, indoor concentrations of a generic volatile organic compound (VOC) as an indicator of non-occupantcontaminant sources, and energy impacts. The results indicate that these impacts are dependent on the details of the spaces including occupancy patterns, ventilation rate requirements in the relevant standards and ventilation system operating schedule as well as the numerous assumptions used in the analysis, including contaminant source strengths and system-off infiltration rates. For the cases studied, the application of CO2 DCV resulted in significant decreases in ventilation rates and energy loadsaccompanied by increased indoor CO2 and VOC concentrations. The increases in CO2 were not particularly significant, in the range of 100 ppm (v). The indoor VOC levels increased by a factor of two or three, but the absolute concentrations were still relatively low based on the assumed emission rates. The annual energy loadreductions due to the use of CO2 control were significant in most of the cases, ranging from 10% to 80% depending on the space type, climate and ventilationstrategy.

Download or read book Modeling Indoor Air Pollution written by Darrell W. Pepper and published by Imperial College Press. This book was released on 2009 with total page 361 pages. Available in PDF, EPUB and Kindle. Book excerpt: Emission of pollutants and their accumulation due to poor ventilation and air exchange are serious problems currently under investigation by many researchers. Of particular concern are issues involving air quality within buildings. Toxic fumes and airborne diseases are known to produce undesirable odors, eye and nose irritations, sickness, and occasionally death. Other products such as tobacco smoke and carbon monoxide can also have serious health effects on people exposed to a poorly ventilated environment; studies indicate that indirect or passive smoking can also lead to lung cancer.Design for prevention or remediation of indoor air pollution requires expertise in optimizing geometrical configurations; knowledge of HVAC systems, perceived or expected contaminants and source locations; and economics. Much of the design concept involves ways in which to optimize the benefits or balance the advantages and disadvantages of various configurations and equipment. The fact that a room or building will conceivably become contaminated is generally an accepted fact OCo to what extent indoor air pollution will become critical is not really known until it happens.A series of numerical models that run in MATLAB are described in the text and placed on the Web. These models include the finite difference method, finite volume method, finite element method, the boundary element method, particle-in-cell, meshless methods, and lagrangian particle transport. In addition, all example problems can be run using COMSOL, a commercial finite-element-based computer code with a great deal of flexibility and application. By accessing AutoCad ICES or DWG file structures, COMSOL permits a building floor plan to be captured and the interior walls discretized into elements.

Download or read book Demand controlled Ventilation and Classroom Ventilation written by William J. Fisk and published by . This book was released on 2009 with total page 154 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Indoor Air Quality Modeling written by Paul David Knoespel and published by . This book was released on 1990 with total page 346 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Simulations of Indoor Air Quality and Ventilation Impacts of Demand Controlled Ventilation in Commercial and Institutional Buildings written by Andrew K. Persily and published by . This book was released on 2003 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Ventilation Solutions Improving Indoor Air Quality written by Charles Nehme and published by Charles Nehme. This book was released on with total page 42 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ventilation is an indispensable aspect of our built environment, yet it often operates quietly in the background, unseen and unheard. It is the invisible force that breathes life into our homes, workplaces, and public spaces, influencing our health, comfort, and overall well-being. The quality of the air we breathe indoors profoundly affects our lives, from our ability to concentrate and be productive to our susceptibility to illnesses and allergies. This book delves into the world of ventilation, unveiling its significance, principles, and applications across diverse settings. Whether you are a homeowner seeking to enhance indoor air quality, an architect striving to create sustainable buildings, or an engineer working on cutting-edge ventilation technologies, this book is a comprehensive guide to understanding, implementing, and optimizing ventilation systems. Ventilation is not a static field; it evolves in response to advancing technologies, changing environmental concerns, and the pursuit of healthier, more efficient indoor environments. In each chapter, we explore different facets of ventilation, from its role in mitigating the spread of respiratory diseases like COVID-19 to its pivotal role in green building practices aimed at reducing our carbon footprint. As we navigate the intricate world of ventilation, we emphasize best practices, emerging trends, and innovative solutions that are shaping the future of indoor environments. Whether you are seeking practical advice for improving ventilation in your home, insights into sustainable building design, or a glimpse into the technologies that will revolutionize the field, this book equips you with the knowledge to make informed decisions and contribute to creating spaces that prioritize health, comfort, and environmental responsibility. In our exploration of ventilation, we aim to illuminate the importance of this often-overlooked aspect of our daily lives. By understanding its principles and embracing best practices, we can breathe easier, work more productively, and live healthier lives in the spaces we call home, work, and play. We invite you to embark on this journey through the world of ventilation, and we hope you find the insights and knowledge within these pages both enlightening and empowering. Sincerely, Charles nehme

Download or read book State of the art Review of CO2 Demand Controlled Ventilation Technology and Application written by Steven J. Emmerich and published by DIANE Publishing. This book was released on 2001 with total page 47 pages. Available in PDF, EPUB and Kindle. Book excerpt: The control of outdoor air intake rates in mechanically ventilated bldgs. based on indoor carbon dioxide (CO2) levels, often referred to as CO2 demand controlled ventilation (DCV), has the potential for reducing the energy consumption assoc. with bldg. ventilation in commercial and institutional bldgs. CO2 DCV has been studied for 20+ years, but questions still remain re: the actual energy savings potential as a function of climate, ventilation system features, and bldg. occupancy. In addition, questions exist as to the indoor air quality impacts of the approach and the best way to implement CO2 DCV in a given bldg. This report presents a state-of-the-art review of CO2 DCV technology and application incl. discussion of the concept and its application, and a literature review.

Download or read book HVAC Controls written by Charles Nehme and published by Charles Nehme. This book was released on with total page 33 pages. Available in PDF, EPUB and Kindle. Book excerpt: Welcome to the world of HVAC controls! This book aims to provide you with a comprehensive understanding of HVAC controls, their importance, and their impact on heating, ventilation, and air conditioning systems in buildings. Heating, ventilation, and air conditioning play a vital role in maintaining indoor comfort, energy efficiency, and occupant well-being. Within these systems, HVAC controls act as the brains, regulating and optimizing the operation of various components to achieve the desired indoor conditions. Without proper control strategies and technologies, HVAC systems would be inefficient, unreliable, and unable to adapt to changing conditions. The field of HVAC controls is constantly evolving, driven by advancements in technology, the need for energy efficiency, and the demand for intelligent and connected buildings. From basic control strategies to advanced technologies like IoT, machine learning, and cloud computing, HVAC controls have come a long way in enhancing system performance and occupant comfort. Throughout this book, we will delve into the fundamental principles of HVAC controls, exploring the different components, sensors, actuators, and control strategies that make up these systems. We will discuss the integration of HVAC controls into building automation systems, the role of controls in energy efficiency and indoor air quality, and the impact of advanced technologies on the future of HVAC controls. We will also address the challenges and considerations in HVAC controls, including system complexity, sensor accuracy, energy efficiency versus occupant comfort, maintenance and troubleshooting, cybersecurity, and evolving industry standards. By understanding and addressing these challenges, we can effectively implement and maintain HVAC controls to ensure optimal system performance and occupant satisfaction. Whether you are a student, a professional in the HVAC industry, a building manager, or simply interested in learning about HVAC controls, this book aims to provide you with a comprehensive and practical guide to understanding and utilizing HVAC controls effectively. It is my hope that this book will serve as a valuable resource, equipping you with the knowledge and insights needed to navigate the world of HVAC controls, make informed decisions, and contribute to the design, operation, and maintenance of efficient and comfortable indoor environments. So, let's embark on this journey together, exploring the fascinating world of HVAC controls and unlocking the potential for energy-efficient, sustainable, and comfortable buildings.

Download or read book WHO Guidelines for Indoor Air Quality written by Elisabeth Heseltine and published by WHO Regional Office Europe. This book was released on 2009 with total page 247 pages. Available in PDF, EPUB and Kindle. Book excerpt: Microbial pollution is a key element of indoor air pollution. It is caused by hundreds of species of bacteria and fungi, in particular filamentous fungi (mould), growing indoors when sufficient moisture is available. This document provides a comprehensive review of the scientific evidence on health problems associated with building moisture and biological agents. The review concludes that the most important effects are increased prevalences of respiratory symptoms, allergies and asthma as well as perturbation of the immunological system. The document also summarizes the available information on the conditions that determine the presence of mould and measures to control their growth indoors. WHO guidelines for protecting public health are formulated on the basis of the review. The most important means for avoiding adverse health effects is the prevention (or minimization) of persistent dampness and microbial growth on interior surfaces and in building structures. [Ed.]

Download or read book The Inside Story written by and published by . This book was released on 1993 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Green Schools written by National Research Council and published by National Academies Press. This book was released on 2007-01-25 with total page 192 pages. Available in PDF, EPUB and Kindle. Book excerpt: Evidence has accumulated that shows that the quality of indoor environments can affect the health and productivity of adults and children. One consequence is that a movement has emerged to promote the design of schools that have fewer adverse environmental effects. To examine the potential of such design for improving education, several private organizations asked the NRC to review and assess the health and productivity benefits of green schools. This report provides an analysis of the complexity of making such a determination; and an assessment of the potential human health and performance benefits of improvements in the building envelope, indoor air quality, lighting, and acoustical quality. The report also presents an assessment of the overall building condition and student achievement, and offers an analysis of and recommendations for planning and maintaining green schools including research considerations.

Download or read book Handbook of Environmental Engineering written by Myer Kutz and published by John Wiley & Sons. This book was released on 2018-10-16 with total page 768 pages. Available in PDF, EPUB and Kindle. Book excerpt: A comprehensive guide for both fundamentals and real-world applications of environmental engineering Written by noted experts, Handbook of Environmental Engineering offers a comprehensive guide to environmental engineers who desire to contribute to mitigating problems, such as flooding, caused by extreme weather events, protecting populations in coastal areas threatened by rising sea levels, reducing illnesses caused by polluted air, soil, and water from improperly regulated industrial and transportation activities, promoting the safety of the food supply. Contributors not only cover such timely environmental topics related to soils, water, and air, minimizing pollution created by industrial plants and processes, and managing wastewater, hazardous, solid, and other industrial wastes, but also treat such vital topics as porous pavement design, aerosol measurements, noise pollution control, and industrial waste auditing. This important handbook: Enables environmental engineers to treat problems in systematic ways Discusses climate issues in ways useful for environmental engineers Covers up-to-date measurement techniques important in environmental engineering Reviews current developments in environmental law for environmental engineers Includes information on water quality and wastewater engineering Informs environmental engineers about methods of dealing with industrial and municipal waste, including hazardous waste Designed for use by practitioners, students, and researchers, Handbook of Environmental Engineering contains the most recent information to enable a clear understanding of major environmental issues.

Download or read book Effectiveness of Variable Ventilation on Indoor Air Quality written by and published by . This book was released on 1997 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ventilation is a method of maintaining good Indoor Air Quality (IAQ). Demand controlled ventilation is a new control strategy that potentially improves IAQ while minimizing energy costs. However, there are several unanswered questions concerning the application of DCV. For example, how well do current CO(2) sensors perform? Under what conditions is DCV cost beneficial? Where is the sensor placement location that results in the highest IAQ. These questions were answered as part of this research program.

Download or read book WHO Guidelines for Indoor Air Quality written by and published by World Health Organization. This book was released on 2010 with total page 488 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book presents WHO guidelines for the protection of public health from risks due to a number of chemicals commonly present in indoor air. The substances considered in this review, i.e. benzene, carbon monoxide, formaldehyde, naphthalene, nitrogen dioxide, polycyclic aromatic hydrocarbons (especially benzo[a]pyrene), radon, trichloroethylene and tetrachloroethylene, have indoor sources, are known in respect of their hazardousness to health and are often found indoors in concentrations of health concern. The guidelines are targeted at public health professionals involved in preventing health risks of environmental exposures, as well as specialists and authorities involved in the design and use of buildings, indoor materials and products. They provide a scientific basis for legally enforceable standards.

Download or read book Modeling of Indoor Air Quality and Exposure written by Niren Laxmichand Nagda and published by ASTM International. This book was released on 1993 with total page 302 pages. Available in PDF, EPUB and Kindle. Book excerpt: